KR100810552B1 - Controller for continuously variable transmission - Google Patents

Abstract

An object of the present invention is to reduce shift shock caused by driving mode switching.

The continuously variable transmission 1 is mounted on a vehicle capable of selecting a plurality of driving modes, and switches the target engine speed for each driving mode. The pulley recipe is controlled by the motor 7. The transmission control ECU 17 outputs a control unit 23 that outputs the target engine speed as a function of the throttle opening degree and the vehicle speed, and a motor that outputs the control value of the motor 7 based on the target engine speed and the actual engine speed. The control value determination unit 24 is provided. The motor control value determiner 24 updates the current target engine speed stepwise when the target engine speed changes by more than a predetermined determination value according to the vehicle speed in accordance with the selection of the travel mode.

Description

Continuously variable transmission control unit {CONTROLLER FOR CONTINUOUSLY VARIABLE TRANSMISSION}

1 is a block diagram showing the main functions of a continuously variable transmission control apparatus according to an embodiment of the present invention.

2 is a system configuration diagram of a continuously variable transmission control apparatus according to an embodiment of the present invention.

3 is a view showing a form in which the target engine speed Netgt is changed.

4 is a diagram illustrating a form in which a target engine speed Netgt is changed.

5 is a flowchart according to the characteristic shift processing of the continuously variable transmission.

FIG. 6 is a diagram showing an example of a map of determination values of differences in target engine speeds. FIG.

FIG. 7 is a flowchart showing a calculation example of a change amount of target engine speed Netgt per unit time. FIG.

8 is a diagram illustrating an example of a map of target engine speed change amount ΔNetgt per other hour according to the vehicle speed.

9 is a diagram illustrating an example of a map of throttle comparison value THv according to vehicle speed.

10 is a diagram showing an example of shift characteristics in a low fuel consumption running mode.

11 is a diagram illustrating an example of shift characteristics in a sport running mode.

<Explanation of symbols for the main parts of the drawings>

1: continuously variable transmission

2: output shaft

3: driven pulley

10: manual pulley

14: V belt

16: manual pulley rpm sensor

17: transmission control ECU

19: mode switch

21: Throttle Sensor

22: engine speed sensor

23: target engine speed calculator

24: motor control value determination unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission control device, and more particularly, to a continuously variable transmission control device suitable for mitigating a shift shock caused by a large change in shift characteristics due to switching of a traveling mode.

For a belt-type continuously variable transmission connected to an internal combustion engine (hereinafter referred to as an "engine"), a control device is known which controls the pulley recipe by sliding the movable side of the drive pulley in the direction of the output axis of the engine by a motor ( Japanese Patent Laid-Open No. 6-123351). This control device searches a map based on the throttle opening and the vehicle speed to determine the target recipe, and drives the motor to obtain the target recipe. In addition, the difference between the target recipe and the actual pulley recipe controls the duty according to the on / off state of the accelerator while increasing the duty ratio of the motor as the difference is larger. By this control, smooth operation of the transmission in accordance with the shift request according to the driving situation is expected.

[Patent Document 1] Japanese Unexamined Patent Publication No. Hei 6-123351

In a vehicle equipped with a continuously variable transmission, it has been considered to adopt a control method of setting a plurality of driving modes of the vehicle and switching the shift characteristics for each of the traveling modes. In such a vehicle, when the shift characteristic is switched in conjunction with the switching of the driving mode, if the target engine speed and the actual engine speed are significantly different, a shift shock occurs when the speed ratio is sharply changed in order to solve the difference in the speed difference. It may damage the gearbox and may affect the durability of the transmission.

It is conceivable to improve the above problems by controlling the duty by the difference between the target value and the actual value as in the control apparatus described in Patent Document 1. However, the shift characteristic switching shock during the switching of the driving mode cannot be sufficiently improved only by the duty adjustment of the motor based on the difference between the pulleys and the demand for better examination.

SUMMARY OF THE INVENTION An object of the present invention is to provide a continuously variable transmission control apparatus capable of reducing shock when shifting the shift characteristic in a continuously variable transmission capable of switching the shift characteristic for each driving mode of the vehicle.

In order to achieve the above object, the present invention provides a control device for a continuously variable transmission capable of selecting a plurality of driving modes, comprising: an actuator for changing a transmission ratio of the continuously variable transmission and a target value output means for outputting a target engine speed as a function of throttle opening and vehicle speed; And shift characteristic determining means for determining the driving direction and the driving speed of the actuator based on the difference between the target engine speed and the actual engine speed, wherein the shift characteristic determining means is presently selected in accordance with the selection of the driving mode. In the case where it is determined that the target engine speed of the engine is changed beyond the predetermined determination value according to the vehicle speed, the shift characteristic shifting means for updating the current target engine speed in stages and shifting to the value after switching of the driving mode is included. There is a characteristic.

The present invention also includes means for determining a throttle opening degree determination value set as a function of the driving mode and the vehicle speed, wherein the shift characteristic shifting means is a driving mode when the current throttle opening degree is greater than the throttle opening degree determination value. According to the second aspect of the present invention, the target engine speed is updated according to the present invention, and when the current throttle opening degree is smaller than the throttle opening degree determination value, the target engine speed is updated according to the driving mode and the vehicle speed.

Further, the present invention has a third feature in that the update speed of the target engine speed is different from that of the case where the target engine speed increases due to the change of the driving mode.

The fourth aspect of the present invention is that the higher the engine speed is, the slower the update speed of the target engine speed is, in accordance with the engine speed when the driving mode is switched.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 2 is a system configuration diagram of a continuously variable transmission control apparatus according to an embodiment of the present invention. The continuously variable transmission 1 is connected to, for example, a crankshaft, that is, an output shaft 2 of an engine (not shown) as a driving source of a non-driving vehicle ATV. The drive pulley 3 consists of the fixed pulley piece 31 and the movable pulley piece 32 provided so that sliding with respect to the output shaft 2 in the axial direction is possible. The slider 5 is supported by the bearing 4 on the outer periphery of the hub of the movable pulley piece 32. A gear 51 is formed on the outer circumference of the slider 5, which meshes with the final gear 64 of the reducer 6, which consists of four gears 61, 62, 63, and 64. The first gear 61 of 6 is engaged with the output gear 71 of the motor 7. The internal thread formed on the inner circumference of the slider 5 is screwed with the external thread formed on the outer circumference of the cylinder 9 fixed to the case 8.

When the slider 5 rotates by the rotation of the motor 7, the female screw of the slider 5 rotates around the male screw of the cylinder 9, and the output shaft 2 is moved by the feeding action of the screw in the axial direction. The slider 5 is moved in the axial direction of. By moving this slider 5, the space | interval of the fixed pulley piece 31 and the movable pulley piece 32 of the drive pulley 3 changes.

The manual pulley 10 of the continuously variable transmission 1 is supported by the manual shaft 11. The manual pulley 10 consists of the movable pulley piece 101 and the fixed pulley piece 102, and both of them are rotatable with respect to the manual shaft 11. In addition, the movable pulley piece 101 is slidable in the axial direction with respect to the passive shaft 11, and biased against the fixed pulley piece 102 by the coil spring 103. The manual shaft 11 is provided with a centrifugal clutch 12, and the movable pulley piece 101 is coupled to the manual shaft 11 through the clutch 12. The passive shaft 11 is coupled to the drive shaft of the ATV via a reducer comprising a gear 13. The drive pulley 3 and the manual pulley 10 are fastened to the V belt 14.

The position sensor 15 which detects the reset position of the movable pulley piece 32 of the drive pulley 3 is provided near the outer periphery of the movable pulley piece 32. In addition, a manual pulley rotation speed sensor 16 that detects the rotation speed of the manual pulley 11 is disposed to face a magnetic body (not shown) that rotates together with the manual pulley 10.

As a control device of the continuously variable transmission 1, a transmission control ECU 17 for driving the motor 7 is provided. The transmission control ECU 17 includes a microcomputer and receives power from the battery 18.

The vehicle is provided with a mode switch 19 for selecting a driving mode. According to the traveling mode, the shift characteristic is selected from the manual mode and the plurality of auto modes. The change switch 20 outputs a change signal CH for switching in a direction of raising or lowering the speed change stage. The change switch 20 is made effective in the manual mode, and the shift stage is selected according to the change signal CH. In the manual mode, the motor 7 is driven to set a predetermined pulley recipe for each shift stage. The pulley ratio is the rotation speed N1 (N1 / N0) of the manual pulley 10 with respect to the rotation speed N0 of the drive pulley 3. The throttle sensor 21 detects the throttle valve opening degree of the engine not shown, and outputs the opening degree information TH. The engine speed sensor 22 detects a reflector installed in the rotor of an unillustrated generator ACG connected to the output shaft of the engine and outputs the engine speed Ne, that is, the engine speed Ne.

State the driving mode. A plurality of driving modes are set, and different shift characteristics correspond to each driving mode. In this embodiment, the sports driving mode and the low fuel consumption driving mode are set as the manual mode and the two auto modes.

In the manual mode, a plurality of speed ratios are set. Then, one of the plurality of speed ratios is instructed by the change switch 20, and the speed ratio is set to be fixed to this and to travel.

In the sport running mode, powerful driving is possible at a higher engine speed than in the manual mode, and in the low fuel consumption running mode, it is set to realize running at a lower engine speed than the manual mode as opposed to the sports running mode. 10 and 11 show examples of shift characteristics of the low fuel consumption driving mode and the sports running mode, respectively.

Fig. 1 is a block diagram showing main part functions of a transmission control device (ECU 17). The target engine speed calculating section 23 calculates the target engine speed Netgt based on the throttle opening degree TH and the vehicle speed V. FIG. For example, it can comprise with the map which outputs the target engine speed Netgt as a function value of the throttle opening degree TH and the vehicle speed V. FIG. This map is provided for each driving mode. The vehicle speed V may be represented by the rotation speed of the manual pulley 10 detected by the manual pulley rotation speed sensor 16.

The motor control value determination unit 24 is a shift characteristic determination means, and the actual engine speed Ne obtained by the target engine speed Netgt and the engine speed sensor 22 calculated by the target engine speed calculation unit 23. Based on the difference of), the rotational direction of the motor 7 and the duty of the motor 7, that is, the motor rotational speed, are determined.

If the target engine speed Netgt is larger than the actual engine speed Ne, the motor 7 is driven in a direction in which the distance between the fixed pulley 31 and the movable pulley 32 is increased to increase the pulley ratio. In addition, when the difference between the target engine speed Netgt and the actual engine speed Ne is larger than the determination value according to the vehicle speed, the target engine speed Netgt is gradually decreased in order to extend the time required for changing the pulley ratio. Change it. Details will be further described later. The motor 7 is driven in accordance with the target engine speed Netgt with the control value output from the motor control value determiner 24, that is, the rotation direction and duty of the motor 7, and the pulley recipe is changed.

In the conventional apparatus, since the target engine speed Netgt is suddenly changed when the driving mode is switched, the shift shock becomes large. On the other hand, in this embodiment, since the target engine speed Netgt is gradually changed when the running mode is switched, the shift shock is reduced.

3 is a diagram illustrating a form in which the target engine speed Netgt is changed when no countermeasure for gradually changing the target engine speed Netgt is taken. Line A is the characteristic of target engine speed Netgt before switching of driving modes, and line B is the characteristic of target engine speed Netgt after switching of driving modes.

It is a figure which shows the example which took the reduction measure of a shift shock. As shown in the figure, the target engine speed Netgt is gradually updated from the line A to the line B over the transition period without switching the target engine speed Netgt immediately to the line B at the time of changing the driving mode. As a result, the shift shock can be reduced. The transition period differs depending on the driving mode and the vehicle speed at the time of switching the driving mode and the driving mode (see FIG. 7).

5 is a flowchart of the characteristic shift processing for gradually changing the target engine speed Netgt. In step S1, it is determined whether the mode switch 19 has been operated, that is, whether the switching of the traveling mode has been performed. If the driving mode has been switched, the process proceeds to step S2 to determine whether the difference between the target engine speed Netgt in the running mode (current mode) before switching and the running mode (following destination mode) after the switching is equal to or greater than the threshold (determined value). It is determined whether or not. The determination value is read out from the map set according to the vehicle speed V. FIG. 6 shows an example of a map showing the relationship between the vehicle speed and the determination value.

If the difference in the target engine speed Netgt is larger than the determination value, the flow advances to step S3 to determine whether the transition mode flag is on or off. The initial value of the transition mode flag is off. Therefore, the first determination is off, and the flow proceeds to step S4 to turn on the transition mode flag. In step S5, as the target engine speed Netgt during the transition period, a value obtained by adding the amount of change per unit time to the current target engine speed Netgt is set.

If it is determined in step S3 that the transition mode flag is turned on, the flow proceeds to step S6, where the change amount per unit time is added to the target engine speed Netgt last time as the target engine speed Netgt during the transition period. Set. In step S7, the transmission control in accordance with the function of FIG. 2 is performed using the target engine speed Netgt during the transition period calculated in step S5 or S6.

If the determination of step S1 or step S2 is negative, the flow advances to step S8 to turn off the transition mode flag. In step S9, the transmission control is performed in accordance with the normal target engine speed Netgt (for example, the line B), which is not during the transition period.

In addition, although the engine speed change amount was added in step S5, S6, when the target engine speed Netgt of a transition destination is small, it subtracts instead of this addition.

7 is a flowchart showing an example of calculating the amount of change in the target engine speed Netgt per unit time. The amount of change determines the transition period. In this calculation example, the amount of change in the target engine speed Netgt is determined by the magnitude of the throttle opening degree TH, by the travel mode and the vehicle speed V, or only by the travel mode.

In Fig. 7, in step S11, the comparison value THv of the throttle opening degree TH is calculated. The comparison value THv is calculated based on the driving mode and the vehicle speed V. FIG. For example, a map in which the throttle comparison value THv is set in relation to the vehicle speed V is provided for each driving mode, and the map can be searched to obtain the comparison value THv.

In step S12, the current throttle opening degree TH is compared with the comparison value THv. When the throttle opening degree TH is small, it progresses to step S13, and calculates the target engine speed change amount (DELTA Netgt) per unit time according to a traveling mode and the vehicle speed V. FIG. For example, a map in which the target engine speed change amount ΔNetgt is set per unit time in relation to the vehicle speed V is provided for each driving mode, and the map is searched to determine the target engine speed change amount Δ Netgt per unit time. You can get it.

If step S12 is negative, that is, if the throttle opening degree TH is larger than the comparison value THv, the process proceeds to step S14, where the target engine speed change amount ΔNetgt is set per unit time according to the traveling mode. Read out.

It is a figure which shows the example of the map which set the target engine speed change amount (DELTA Netgt) per unit time according to vehicle speed. This map is set for each driving mode, and is preferably provided for addition and subtraction respectively. In addition, by using different maps for addition and subtraction respectively, the length of the transition period is different. For example, the addition use makes the target engine speed change amount? Netgt per unit time corresponding to the vehicle speed smaller than the reduction use.

9 is a diagram illustrating an example of a map in which a throttle comparison value THv corresponding to the vehicle speed used in step S11 is set. The map is set for each driving mode.

Further, as the engine speed Ne becomes larger according to the engine speed Ne when the driving mode is switched, the transition time may be longer, that is, the target engine speed change amount? Netgt per unit time may be reduced.

According to the present invention having the above characteristics, in the case where a change in the transmission characteristic that greatly changes the engine speed is required following the switching of the driving mode, the change in the required engine speed will be larger than the determination value considering the vehicle speed at that time. At this time, the target engine speed can be changed in steps so that the engine speed can be changed gradually. By gradually changing the target engine speed, the movement of the actuator is weakened, and the shift shock is reduced by this operation so that discomfort may not occur to the driver, and durability can be improved.

In particular, according to the invention having the second aspect, when the current throttle opening degree is larger than the determination value suitable for the driving mode and the vehicle speed, that is, when it is determined that the vehicle is being accelerated, the shift characteristic is changed according to the amount of change set according to the driving mode regardless of the vehicle speed. Is changed. On the other hand, when the current throttle opening degree is smaller than the determination value, that is, when it is determined that the vehicle is decelerating, the shift characteristic is changed in accordance with the change amount set in consideration of the vehicle speed in addition to the driving mode. This is because the shift shock tends to change depending on the vehicle speed during deceleration, so that a fine change can be made depending on the vehicle speed.

According to the invention having the third feature, the switching speed can be changed by increasing and decreasing the engine speed. This is because shift shock is different between increasing and decreasing engine speed.

According to the invention having the fourth feature, since the shift shock is larger as the current engine speed is larger, the shift time to the target engine speed is longer as the engine speed is larger, thereby making it easier to alleviate the shift shock.

Claims (4)

In the continuously variable transmission control apparatus which can select the driving mode from which a some transmission characteristic differs, Means for detecting a throttle opening; Means for detecting a speed of the vehicle; Means for detecting engine speed; An actuator for changing a speed ratio of the continuously variable transmission; Target value output means for outputting a target engine speed as a function of throttle opening and vehicle speed; And Shifting characteristic determining means for determining a driving direction and a driving speed of the actuator based on the difference between the target engine speed and the detected actual engine speed,  When the shift characteristic determining means determines that the difference between the target engine speed after switching of the driving mode and the target engine speed before switching of the driving mode is greater than or equal to the determination value set according to the vehicle speed, in accordance with the change of the driving mode, the current target engine rotation. And a shift characteristic shifting means for updating the number in stages to shift to the target engine speed after switching the driving mode. 2. The apparatus according to claim 1, comprising means for determining a throttle opening degree determination value set as a function of the driving mode and the vehicle speed, The shift characteristic shifting means updates the target engine speed in accordance with the traveling mode when the current throttle opening degree is greater than the throttle opening degree determination value. And the target engine speed is updated according to the driving mode and the vehicle speed when the current throttle opening degree is smaller than the throttle opening degree determination value. The continuously variable transmission control apparatus according to claim 1, wherein the update speed of the target engine speed is different from the case where the target engine speed increases or decreases due to the switching of the driving mode. The continuously variable transmission control device according to claim 1, wherein the higher the engine speed detected at the time of switching the driving mode, the slower the update speed of the target engine speed is.

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